Hey guys, I finally tore into my '82 1100 interstate today, and thought I'd post my mistake so hopefully it will save someone else a little time. I did the conversion without taking my upper fairing off, just pulled the tank cover and air box. After getting it all back together, it fired right up. I tried to take it down the road, but as soon as I put a little load on the engine or tried to rev it, it sputtered and acted like it was dropping down to 2 cylinders working. I tore it all back apart, and discovered that there was a green wire that was originally grounded at the front side of the original coil mount. I was kinda working blind because of the upper fairing, and just didn't notice it. I grounded that wire, and now the bike runs better than ever before. One other thing to mention, my bike had a large ceramic resistor, which looked kinda like the ones used in old chevys. I did leave it inline, just in case.
In my opinion, this upgrade is well worth the time and money. I purchased a new coil and a set of bosch plug wires from Herko down in Miami, and including shipping it cost me less than $35.